


A Good Idea

by sadistically_sweet



Category: Sherlock (TV)
Genre: Age Play, Caregiver Greg, Fluff, Little mycroft, M/M, Non-Sexual Age Play, Other Additional Tags to Be Added, Some angst
Language: English
Status: In-Progress
Published: 2018-01-10
Updated: 2018-02-04
Packaged: 2019-03-03 01:43:52
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,684
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13330830
Author URL: https://archiveofourown.org/users/sadistically_sweet/pseuds/sadistically_sweet
Summary: Mycroft has always begrudgingly admitted that he and his brother are similar in several different ways. What happens when Greg finally persuades him to explore one more?





	1. Part One

**Author's Note:**

> Based on a prompt, found here: https://sadieandmo.tumblr.com/post/168005229096/this-might-not-fit-with-your-characterization-of
> 
> "This might not fit with your characterization of Mycroft, but I can sorta imagine him and Sherlock being little and being supervised by John and Papa Lestrade. What are your thoughts? Is it unrealistic or plausible? "

“Okay, yeah, just–just wait right here, I’ll go get him. Yeah.”

Greg headed upstairs, treading lightly because he’s still used to creaking stairs even though these particular stairs are marble, not wood.

He hoped this was a good idea.

He eased the door to the bedroom open a sliver, and silently squeezed himself inside the darkened room.

He _really_ hoped this was a good idea.

It had to be.

Leaving the door open a crack so he wouldn’t bust his toes or crack his shins, Greg made his way over to the side of the bed closest to the door…which was usually *his* side, but not today.

He sat down on the edge and patted part of the great big lump of blanket next to him. “Hey, lovey…” he said quietly; “Naptime’s over.”

The lump stirred slightly, burrowing deeper into the rest of the blankets.

Greg gave the lump a firmer pat. “C’mon, it’s time to wake up,” he said, no longer whispering. He reached over and clicked on the bedside lamp, and the lump whinged.

“Ah-ah, Mikey. You’ve slept a long time, and besides, we’ve got–” Greg stopped mid-sentence and barked out a laugh when he looked down at the lump and saw a very grouchy Mycoft glaring back up at him from underneath a corner of blanket. “Good afternoon to you too, Sunshine,” Greg grinned.

Mycroft’s frown deepened. “No.”

“ ‘No’, what? No to getting up?”

Mycroft’s face disappeared. “…No. No Mikey.”

Ah. “I’m sorry, I forgot,” Greg said, and he meant it with all sincerity. When Mycroft had agreed to do this, to ‘give it a try’, he’d laid out a short but thorough list of things (”Limits,” he’d said) that absolutely would _not_ be happening during the…during the ‘trying phase’, under the threat of celibacy until Greg’s cock ‘dried up and fell off’, should any of those limits be breached.

Calling him ‘Mikey’, as Greg had originally suggested, was on that list. Other names were fine-ish (as long as they weren’t gag-worthy or meant for teasing), but Mikey was strictly not. It had been tough as nails to get Mycroft to finally agree to this, even after the list had been made and discussed, and Greg was determined not to fuck this up. “I’m very sorry,” he said again, and rubbed his hand up and down the pile of blankets. “It won’t happen again.”

The lump shifted, but didn’t pull away. Okay. That was good. Greg bent down and slowly lifted the corner of the blanket out of the way. “…Would it make it better if I said there’s something downstairs for you?”

Mycroft peered at him from underneath the blankets, his only response was to blink.

Christ. Greg had never remembered just how much Myc favoured his brother until he did something like that. “Yeah, it’s waiting on us downstairs,” he said, giving Mycroft a reassuring smile. “Should we go see?”

Finally, Mycroft nodded (Greg had noticed that in headspace, Mycroft was a man of even fewer words than he was as an adult…fewer as in, if he didn’t _have_ to speak, he wouldn’t) and, after letting Greg pull back the blankets, sat up.

Greg’s smile broadened. Fluffy, sleep-mussed Mycroft with his hair sticking out all over was always a favorite of his, but the added layer of vulnerability that the baby-soft fleece pajama top that had been borrowed from Sherlock’s stash, with the image of a baby bear cradled sleepily in a smiling crescent moon was the topping on the adorable little cake.

And the matching blue cotton training pants (nappies had been the first thing on the list of ‘Fuck No’s’), the icing. “Here,” Greg held out his hands. “Toilet first, then we’ll go see what’s down there.”

Mycroft stared at him a moment as he sat there, considering Greg’s offer.

Greg held his breath while keeping the smile steady on his face.

… _Please_ , let this be a good idea.

Mycroft finally held his hands out as well, letting Greg take them and help him stand up. The look on his face made it painfully obvious that he still wasn’t fully comfortable.

Seeing this, Greg slowly wrapped one arm around Mycroft’s waist, giving him plenty of time to shake his head ‘no’ or pull away if he wanted–which he didn’t, thankfully…although he was watching Greg very closely–and pulled him into a warm hug.

“Good boy,” he murmured when he felt Mycroft gradually raise his arms to hug Greg back. He rubbed his hand up and down the lean man’s back, stopping at his bottom.

He felt Mycroft stiffen. “No, shh…you’re a good boy,” Greg murmured, and began to pat his backside, confirming that yes, this is different and I know you’re scared but this is okay and I love you.

At the steady, continued patting, he felt Mycroft go slack in his arms. “Yeah, there we go. It’s okay,” Greg said, stepping back.

Mycroft’s cheeks were flushed a charming shade of pink that Greg thought suited him very well, especially when you considered his current get-up. Obviously, the bum-patting had worked; Mycroft’s headspace seemed a bit more reinforced, and the same softness that he’d so often watched slip into Sherlock’s eyes when he regressed was now taking the edge out of his lover’s.

Greg took his hand and gave it a squeeze, delighting when Mycroft squeezed his fingers back. “Such a good boy,” he said again, taking a praising tone. “Staid dry all through your nap!”

Mycroft’s cheeks blushed darkly as Greg pulled him towards the bathroom, still heaping the praise for all it was worth (and with both Holmes brothers, that meant a _lot_ ); “Let’s keep that good luck going and use the toilet like a big boy, yeah? You did so well keeping dry, my clever little man. I’m impressed.”

Mycroft just nodded as he shuffled along after Greg, still blushing at the praise and chewing at the knuckle of his thumb.

Greg looked back at him and brightened.

This _was_ a good idea.


	2. Part Two

Greg waited at the door patiently while Mycroft washed his hands…which, Greg sheepishly realized, he hadn’t even asked him to. Some caregiver he was.

‘ _Rookie mistake_ ,’ he told himself. ‘ _You’ve been taking care of the boys for how long now, and today of all days you start mucking it up_.’ “Good boy,” he said out loud as he shut off the tap, while watching Mycroft’s reaction in the mirror.

Mycroft was still blushing–hadn’t stopped since he woke up, really–and kept his gaze down, refusing to look at Greg.

He wasn’t very pleased with him right now, after the toilet, uh… _experience_.

Instead of letting Mycroft use the toilet normally, Greg had made him sit down for a wee…mostly for the practicality of it, and partly just so Greg could get to see his reaction. Which had been adorable, as expected.

And it made him the tiniest bit sulky (’tiny’ in terms of a Holmes being sulky, at least). Which had been even more adorable–that pout of his had a lot of charm behind it when it wasn’t accompanied by a sneer, just like his little brother.

 Greg took the hand towel from the holder on the wall and dried Mycroft’s hands, taking each one in turn and sort of giving him a mini-massage by gently rubbing the knuckles and in between each finger, as well as his palms.

Small details were important to Mycroft, no matter what his headspace, so small details were what Greg was going to try harder to focus on (like the handwashing…seriously, he was used to doing this with the boys on a near-weekly basis; it shouldn’t be this bloody difficult to keep in mind now). Because he wanted this to be as enjoyable an experience for him as possible.

Because this was a good idea.

And it seemed to do the trick; Mycroft’s shoulders’ relaxed at Greg’s attention, and he finally looked up at him through his lashes, head still tipped down.

“There,” Greg said as he hung the towel back up, and gave Mycroft’s forehead a kiss as he leaned forward. “Are you ready to see what’s waiting for us?”

Mycroft nodded, and Greg watched him lift his closed fist to his mouth and go to suck on the back of his thumb, rather than the whole thing…Greg grinned as he watched his face pucker slightly at the taste of leftover soap still remaining on his skin, but apparently that wasn’t too much of a deterrent because that thumb stayed exactly where it was.

“You’re so cute,” Greg chuckled, and ushered Mycroft out of the room with a hand at the small of his back.

“Nnn,” the other man grunted.

It sounded like a pretty neutral grunt to Greg, but then again, knowing Mycroft?…it probably meant ‘no’, anyway. “Yes, you are,” Greg replied with a meaningful pat to a plushly-padded bum; “You’re cute, you’re sweet, and best of all, you’re all mine.”

Mycroft kept his head tipped down, and went quiet.

That is, until they reached the top of the stairs.

As Mycroft went to take that first step off the landing, the hand that Greg had on his bum was suddenly in front and pressing at his tummy, holding him back. “Ah-ah, you know the rules.”

This made Mycroft stop short in his tracks and finally lift his head to peer at Greg, puzzled, with his foot hovering over the first step.

“No, you know how we do things around here,” Greg said. “What’s the rule about the steps.”

Mycroft blinked at him owlishly.

“Mike–sweetheart,” Greg caught himself before he could repeat his earlier mistake and use the wrong name at the wrong time. “You know well enough that little boys don’t go down these steps on their own.”

He could see the corner’s of Mycroft’s mouth turn down around his thumb. “Uh-huh, same rules for everyone, love.” Greg held out his hand and wiggled his fingers. “Hold my hand.”

Mycroft’s frown deepened as he glared down at Greg’s waiting hand, causing his brow to furrow. 

Greg waggled his fingers again and this time, with much reluctance, Mycroft slowly reached out and took his hand. 

“There’s a good lad. Now hold on to the banister.”

Mycroft’s head snapped up fast enough to make Greg wonder if he’d actually gotten dizzy (because he sure as hell did just from watching), and stared at him as if he’d grown a second head.

Greg already knew the problem…he’d gone through the same thing with Jawn and Sherlock both. Multiple times. “Yes,” he said, nodding his head towards Mycroft’s mouth. “That means that thumb has to come out. Just for a little while,” he was quick to add.

Mycroft’s flustered glare quickly devolved into a pure scowl…and even being dressed like an infant with his thumb in his mouth did little to diminish the effect of a true Holmes’ Scowl ™ .

Good thing Greg was immune by now, having been on the receiving end of one many, _many_ times before. “Mm-mm, no. Those are the rules.” ‘ _The rules that **you** made, you tit,_ ’, he added silently.

Mycroft’s eyes widened momentarily–it must have been quite a shock for him to be told ‘no’ still, Greg thought– before his expression returned to that sour pucker of his. With a stomp of his foot, he yanked his hand out of Greg’s and whirled around, turning his back to him.

“Ah, now see…that’s just going to get you left up here by yourself while I go enjoy our secret downstairs.” Greg turned to do just that, and barely made it to the second step before a loud “NO!” stopped him. He looked over his shoulder.

Mycroft was now facing him again, only this time his hands (both of them) were at his sides, balled into fists, and there was a noticeable wobble to his bottom lip that belied his glare. Which wasn’t even a glare so much anymore, as much as an attempt to keep from pouting.

Which was the cutest eff’ing thing to Greg…he couldn’t help but grin, in spite of the ‘stern’ front he was trying to pull off.

“Yeah, good choice. I don’t like being left alone, either.” Greg offered his hand to Mycroft again. “And look, your thumb left all on it’s own…might as well take the banister and come down with me anyway, since he’s out of the way and all.”

The grinning seemed to put Mycroft at ease again, and the rest of his grumpy facade fell away with just the tiniest bit of a pouty lip left behind. He took Greg’s hand without any hesitation this time and held onto the banister with the other before coming down to join Greg.

Greg just stood there for a moment, beaming like an idiot. He genuinely couldn’t be more proud of his little guy; “Look at you, making all the right choices today,” he said, and brought Mycroft’s hand up to his lips to place a kiss on his knuckles.

The blush returned to Mycroft’s cheeks in an instant, and he dipped his head again…

…but not before Greg caught the tiny hint of a smile.

Greg’s heart melted…seriously, this was the best idea ever. It didn’t matter how the rest of the day went–that was a moment of pure gold.

They finally made their way down the stairs–slowly, one step at a time, and with Greg counting each one out loud, just like he did with the other boys. Of course, Mycroft didn’t join in the way they did, but that was okay…he wasn’t scowling anymore, and that was all that mattered.

“Annnnnnd, seventeen! Good job!” Greg cheered as they reached the bottom step. He held his and Mycroft’s hands aloft like a pair of winning boxers, and Mycroft had just won the grand title or championship, whatever it is that boxers win; “Yaaaay!”

Mycroft giggled–actually _giggled,_ and pulls his hand out of Greg’s…though playfully this time. “Noooooooo.”

“Yeeeees", Greg teased and poked the bit of Mycroft’s tummy that was showing above the waist of his training pants, making him giggle again and twist away. “ _Nooooooo_!”

Greg laughed; “Okay, okay, Greg’ll stop. So, you ready for your surprise, or should we go back upstairs and go back to bed?!?”

Mycroft, who was smiling just as brightly as Greg was from ear-to-ear, shook his head. “No!” he giggled, and rocked forward on his toes.

“Okay, Happy Feet,” Greg chuckled. “But you gott'a close your eyes first.”

Once again, there was no hesitation before Mycroft did exactly as Greg asked and closed his eyes, squinching them shut tight.

Greg couldn’t believe it….this was _working_!

He moved behind Mycroft and put his hands on his hips, then started to move them to the sitting room. “No peeking! Keep those peeper’s shut!”

“No!” Mycroft chirped, and covered his own eyes with his hands.

They came to a stop in the entrance way to the room. “Now, wait for it…” Greg said, while Mycroft practically bounced on his toes; “…wait…waaaaaiiiiit…now!”

Mycroft dropped his hands….and the giggling stopped. The bouncing stopped. He froze.

John looked up from where he sat on the sofa, his mouth dropping open slightly. Sherlock looked up from where he sat at John’s feet, where he was in the midst of building an elaborate castle, and gasped. “HI, MY’COFF!” he called out, and waved his brother over excitedly.

Greg went to prod Mycroft along into the room; “Look who came to play, say ‘hi’, Mycro–!” Greg was cut short as Mycroft’s head whipped around like the possessed girl from that old movie he saw only once as a kid (that had given him nightmares for months afterwards…hence the ‘only once’ part).

Just as sure as the look on Mycroft’s face was going to be giving him nightmares now…if he didn’t spontaneously combust first, that it.

Okay, so…this might not have been the best idea.


End file.
